No Hidden .Spotlight Folder, Please

To get rid of the hidden `.spotlight` folder on removable volumes like flash drives, `cd` to the volume and then:

touch .metadata_never_index

This tip compliments of Cro Magnon on the Ars technica Mac forum, and [Mac OS X Hints](http://www.macosxhints.com/article.php?story=20060814124808745), from whence it came.